3 years ago

Cos²x - 2 sin²x = -2 .Help me to solve it

Mathematics

1 answer:

Alex777 [14]3 years ago

7 0

Step-by-step explanation:

note that

sin²x = (1-cos²x)

LHS= cos²x - 2 sin²x

= cos²x - 2(1-cos²x)

= cos²x - 2 + 2cos²x

= 3cos²x - 2

cos²x = (1-sin²x)

LHS= cos²x - 2 sin²x

=1-sin²x - 2 sin²x

= 1-3sin²x

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Cos²x - 2 sin²x = -2 .Help me to solve it ​

Cos²x - 2 sin²x = -2 .Help me to solve it